CSS / Styling in community-theme-default - where to start?

I wish to make a few styling changes to the theme myself, but it seems that any editing I do doesn’t apply. It’s clear the issue lies with me and I’m looking in the wrong places, so I’d like some help with direction. For example, I’d like to give this search bar a curved border with border-radius: 4px; or something similar. I’ve tried editing css in theme/css/global.css, theme/modules/blocksearch/blocksearch.css, theme/css/modules/blocksearch/blocksearch.css and store/modules/blocksearch/blocksearch.css but it doesn’t seem to work. Where should I be looking exactly?

@lesley I’ve tried both blocksearch.css and tried targeting that element, but I still can’t see any changes. The only change I can see is by deleting everything in theme/modules/blocksearch/blocksearch.css, it will move the search bar up slightly.

@CaitlynMSL Thank you so much for bringing up this topic. I use the Transformer theme, which I love, and only had the magnifying glass on my page. I finally decided to hunt down how to get the border around the search box. All I had to do was choose “no” for “simple style” in the QUICK SEARCH BLOCK MOD.